JSFiddle - React, Tailwind, and code Playground

HTML

You should be able to type in these and "backspace" should work.<br/><input/><input readonly="readonly" value="test"/><br/>
But it shouldn't work to trigger the back button anywhere.

JavaScript

document.onkeydown = function (event) {
        var doPrevent = false;
        var keyCode = event.charCode ? event.charCode : event.keyCode;

        if(keyCode !== 8){
            return;
        }
        
        var d = event.srcElement || event.target;
        if ((d.tagName.toUpperCase()==='INPUT' && 
                (d.type.toUpperCase()==='TEXT' || d.type.toUpperCase()==='PASSWORD')) 
            || d.tagName.toUpperCase() === 'TEXTAREA') {

            doPrevent = d.readOnly || d.disabled;
        }
        else {
            doPrevent = true;
        }

        if (doPrevent) {
            event.preventDefault();
        }
    };